Woods metal is a low melt point eutectic alloy that is an excellent material for casting ballast. This metal is a superior material for casting nose weights, ballast slugs or even keels for model sailboats. What makes this material so useful is it’s incredibly low melting temperature of 158°F. This metal also has another interesting property. As it cools it shrinks slightly and then re-expands to it original cast size once fully cooled.
The low melting temperature makes it much safer to cast than lead and you do not have to worry about it exploding if it comes into contact with water. This metal can be melted in hot water and spooned into molds or even directly into the nose of you aircraft.
Woods metal is comprised of Bismuth, Lead, Tin and Cadmium, so you must handle it with same precautions as you would lead; work in a well ventilated area and do not allow the liquified metal to come in contact with bare skin.